Naturally occurring
barium (
56Ba) is a mix of six stable
isotope
Isotopes are two or more types of atoms that have the same atomic number (number of protons in their nuclei) and position in the periodic table (and hence belong to the same chemical element), and that differ in nucleon numbers (mass numb ...
s and one very long-lived radioactive primordial isotope, barium-130, identified as being unstable by geochemical means (from analysis of the presence of its daughter xenon-130 in rocks) in 2001.
This nuclide decays by
double electron capture
Double electron capture is a decay mode of an atomic nucleus. For a nuclide (''A'', ''Z'') with a number of nucleons ''A'' and atomic number ''Z'', double electron capture is only possible if the mass of the nuclide (''A'', ''Z''−2) is lower.
...
(absorbing two electrons and emitting two neutrinos), with a half-life of (0.5–2.7)×10
21 years (about 10
11 times the age of the universe).
There are a total of thirty-three known
radioisotope
A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is a nuclide that has excess nuclear energy, making it unstable. This excess energy can be used in one of three ways: emitted from the nucleus as gamma radiation; transferr ...
s in addition to
130Ba. The longest-lived of these is
133Ba, which has a half-life of 10.51 years. All other radioisotopes have half-lives shorter than two weeks. The longest-lived
isomer is
133mBa, which has a half-life of 38.9 hours. The shorter-lived
137mBa (half-life 2.55 minutes) arises as the decay product of the common fission product
caesium-137
Caesium-137 (), cesium-137 (US), or radiocaesium, is a radioactive isotope of caesium that is formed as one of the more common fission products by the nuclear fission of uranium-235 and other fissionable isotopes in nuclear reactors and nucle ...
.
Barium-114 is predicted to undergo
cluster decay, emitting a nucleus of stable
12C to produce
102Sn. However this decay is not yet observed; the upper limit on the branching ratio of such decay is 0.0034%.
List of isotopes
, -
, rowspan=4,
114Ba
, rowspan=4 style="text-align:right" , 56
, rowspan=4 style="text-align:right" , 58
, rowspan=4, 113.95068(15)
, rowspan=4, 530(230) ms
.43(+30−15) s,
β+,
p (99.59%)
,
113Xe
, rowspan=4, 0+
, rowspan=4,
, rowspan=4,
, -
,
α (.37%)
,
110Xe
, -
, β
+ (.04%)
,
114Cs
, -
,
CD (<.0034%)
[Cluster decay is predicted but had never been observed.]
,
102Sn,
12C
, -
, rowspan=2,
115Ba
, rowspan=2 style="text-align:right" , 56
, rowspan=2 style="text-align:right" , 59
, rowspan=2, 114.94737(64)#
, rowspan=2, 0.45(5) s
, β
+
,
115Cs
, rowspan=2, (5/2+)#
, rowspan=2,
, rowspan=2,
, -
, β
+, p
,
114Xe
, -
, rowspan=2,
116Ba
, rowspan=2 style="text-align:right" , 56
, rowspan=2 style="text-align:right" , 60
, rowspan=2, 115.94138(43)#
, rowspan=2, 1.3(2) s
, β
+
,
116Cs
, rowspan=2, 0+
, rowspan=2,
, rowspan=2,
, -
, β
+, p
,
115Xe
, -
, rowspan=3,
117Ba
, rowspan=3 style="text-align:right" , 56
, rowspan=3 style="text-align:right" , 61
, rowspan=3, 116.93850(32)#
, rowspan=3, 1.75(7) s
, β
+
,
117Cs
, rowspan=3, (3/2)(+#)
, rowspan=3,
, rowspan=3,
, -
, β
+, α
,
113I
, -
, β
+, p
,
116Xe
, -
, rowspan=2,
118Ba
, rowspan=2 style="text-align:right" , 56
, rowspan=2 style="text-align:right" , 62
, rowspan=2, 117.93304(21)#
, rowspan=2, 5.2(2) s
, β
+
,
118Cs
, rowspan=2, 0+
, rowspan=2,
, rowspan=2,
, -
, β
+, p
,
117Xe
, -
, rowspan=2,
119Ba
, rowspan=2 style="text-align:right" , 56
, rowspan=2 style="text-align:right" , 63
, rowspan=2, 118.93066(21)
, rowspan=2, 5.4(3) s
, β
+
,
119Cs
, rowspan=2, (5/2+)
, rowspan=2,
, rowspan=2,
, -
, β
+, p
,
118Xe
, -
,
120Ba
, style="text-align:right" , 56
, style="text-align:right" , 64
, 119.92604(32)
, 24(2) s
, β
+
,
120Cs
, 0+
,
,
, -
, rowspan=2,
121Ba
, rowspan=2 style="text-align:right" , 56
, rowspan=2 style="text-align:right" , 65
, rowspan=2, 120.92405(15)
, rowspan=2, 29.7(15) s
, β
+ (99.98%)
,
121Cs
, rowspan=2, 5/2(+)
, rowspan=2,
, rowspan=2,
, -
, β
+, p (.02%)
,
120Xe
, -
,
122Ba
, style="text-align:right" , 56
, style="text-align:right" , 66
, 121.91990(3)
, 1.95(15) min
, β
+
,
122Cs
, 0+
,
,
, -
,
123Ba
, style="text-align:right" , 56
, style="text-align:right" , 67
, 122.918781(13)
, 2.7(4) min
, β
+
,
123Cs
, 5/2(+)
,
,
, -
,
124Ba
, style="text-align:right" , 56
, style="text-align:right" , 68
, 123.915094(13)
, 11.0(5) min
, β
+
,
124Cs
, 0+
,
,
, -
,
125Ba
, style="text-align:right" , 56
, style="text-align:right" , 69
, 124.914473(12)
, 3.5(4) min
, β
+
,
125Cs
, 1/2(+#)
,
,
, -
,
126Ba
, style="text-align:right" , 56
, style="text-align:right" , 70
, 125.911250(13)
, 100(2) min
, β
+
,
126Cs
, 0+
,
,
, -
,
127Ba
, style="text-align:right" , 56
, style="text-align:right" , 71
, 126.911094(12)
, 12.7(4) min
, β
+
,
127Cs
, 1/2+
,
,
, -
, style="text-indent:1em" ,
127mBa
, colspan="3" style="text-indent:2em" , 80.33(12) keV
, 1.9(2) s
,
IT
,
127Ba
, 7/2−
,
,
, -
,
128Ba
, style="text-align:right" , 56
, style="text-align:right" , 72
, 127.908318(11)
, 2.43(5) d
, β
+
,
128Cs
, 0+
,
,
, -
,
129Ba
, style="text-align:right" , 56
, style="text-align:right" , 73
, 128.908679(12)
, 2.23(11) h
, β
+
,
129Cs
, 1/2+
,
,
, -
, rowspan=2 style="text-indent:1em" ,
129mBa
, rowspan=2 colspan="3" style="text-indent:2em" , 8.42(6) keV
, rowspan=2, 2.16(2) h
, β
+
,
129Cs
, rowspan=2, 7/2+#
, rowspan=2,
, rowspan=2,
, -
, IT
,
129Ba
, -
,
130Ba
[Primordial radioisotope]
, style="text-align:right" , 56
, style="text-align:right" , 74
, 129.9063208(30)
, 1.6(±1.1)×10
21 y
,
Double EC
,
130Xe
, 0+
, 0.00106(1)
,
, -
, style="text-indent:1em" ,
130mBa
, colspan="3" style="text-indent:2em" , 2475.12(18) keV
, 9.54(14) ms
, IT
, ''
130Ba''
, 8−
,
,
, -
,
131Ba
, style="text-align:right" , 56
, style="text-align:right" , 75
, 130.906941(3)
, 11.50(6) d
, β
+
,
131Cs
, 1/2+
,
,
, -
, style="text-indent:1em" ,
131mBa
, colspan="3" style="text-indent:2em" , 187.14(12) keV
, 14.6(2) min
, IT
,
131Ba
, 9/2−
,
,
, -
,
132Ba
, style="text-align:right" , 56
, style="text-align:right" , 76
, 131.9050613(11)
, colspan=3 align=center,
Observationally Stable
Stable nuclides are nuclides that are not radioactive and so (unlike radionuclides) do not spontaneously undergo radioactive decay. When such nuclides are referred to in relation to specific elements, they are usually termed stable isotopes.
Th ...
[Believed to undergo β+β+ decay to 132Xe with a ]half-life
Half-life (symbol ) is the time required for a quantity (of substance) to reduce to half of its initial value. The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable at ...
over 300×1018 years
, 0+
, 0.00101(1)
,
, -
,
133Ba
, style="text-align:right" , 56
, style="text-align:right" , 77
, 132.9060075(11)
, 10.51(5) y
, EC
,
133Cs
, 1/2+
,
,
, -
, rowspan=2 style="text-indent:1em" ,
133mBa
, rowspan=2 colspan="3" style="text-indent:2em" , 288.247(9) keV
, rowspan=2, 38.9(1) h
, IT (99.99%)
,
133Ba
, rowspan=2, 11/2−
, rowspan=2,
, rowspan=2,
, -
, EC (.0096%)
,
133Cs
, -
,
134Ba
, style="text-align:right" , 56
, style="text-align:right" , 78
, 133.9045084(4)
, colspan=3 align=center, Stable
[Theoretically capable of spontaneous fission]
, 0+
, 0.02417(18)
,
, -
,
135Ba
, style="text-align:right" , 56
, style="text-align:right" , 79
, 134.9056886(4)
, colspan=3 align=center, Stable
, 3/2+
, 0.06592(12)
,
, -
, style="text-indent:1em" ,
135mBa
, colspan="3" style="text-indent:2em" , 268.22(2) keV
, 28.7(2) h
, IT
,
135Ba
, 11/2−
,
,
, -
,
136Ba
, style="text-align:right" , 56
, style="text-align:right" , 80
, 135.9045759(4)
, colspan=3 align=center, Stable
, 0+
, 0.07854(24)
,
, -
, style="text-indent:1em" ,
136mBa
, colspan="3" style="text-indent:2em" , 2030.466(18) keV
, 308.4(19) ms
, IT
,
136Ba
, 7−
,
,
, -
,
137Ba
, style="text-align:right" , 56
, style="text-align:right" , 81
, 136.9058274(5)
, colspan=3 align=center, Stable
, 3/2+
, 0.11232(24)
,
, -
, style="text-indent:1em" ,
137m1Ba
, colspan="3" style="text-indent:2em" , 661.659(3) keV
, 2.552(1) min
, IT
,
137Ba
, 11/2−
,
,
, -
, style="text-indent:1em" ,
137m2Ba
, colspan="3" style="text-indent:2em" , 2349.1(4) keV
, 0.59(10) µs
,
,
, (17/2−)
,
,
, -
,
138Ba
[ Fission product]
, style="text-align:right" , 56
, style="text-align:right" , 82
, 137.9052472(5)
, colspan=3 align=center, Stable
, 0+
, 0.71698(42)
,
, -
, style="text-indent:1em" ,
138mBa
, colspan="3" style="text-indent:2em" , 2090.54(6) keV
, 800(100) ns
,
,
, 6+
,
,
, -
,
139Ba
, style="text-align:right" , 56
, style="text-align:right" , 83
, 138.9088413(5)
, 83.06(28) min
, β
−
,
139La
, 7/2−
,
,
, -
,
140Ba
, style="text-align:right" , 56
, style="text-align:right" , 84
, 139.910605(9)
, 12.752(3) d
, β
−
,
140La
, 0+
,
,
, -
,
141Ba
[ Fission product]
, style="text-align:right" , 56
, style="text-align:right" , 85
, 140.914411(9)
, 18.27(7) min
, β
−
,
141La
, 3/2−
,
,
, -
,
142Ba
[ Fission product]
, style="text-align:right" , 56
, style="text-align:right" , 86
, 141.916453(7)
, 10.6(2) min
, β
−
,
142La
, 0+
,
,
, -
,
143Ba
[ Fission product]
, style="text-align:right" , 56
, style="text-align:right" , 87
, 142.920627(14)
, 14.5(3) s
, β
−
,
143La
, 5/2−
,
,
, -
,
144Ba
[ Fission product]
, style="text-align:right" , 56
, style="text-align:right" , 88
, 143.922953(14)
, 11.5(2) s
, β
−
,
144La
, 0+
,
,
, -
,
145Ba
, style="text-align:right" , 56
, style="text-align:right" , 89
, 144.92763(8)
, 4.31(16) s
, β
−
,
145La
, 5/2−
,
,
, -
, rowspan=2,
146Ba
, rowspan=2 style="text-align:right" , 56
, rowspan=2 style="text-align:right" , 90
, rowspan=2, 145.93022(8)
, rowspan=2, 2.22(7) s
, β
− (99.98%)
,
146La
, rowspan=2, 0+
, rowspan=2,
, rowspan=2,
, -
, β
−,
n (.02%)
,
145La
, -
, rowspan=2,
147Ba
, rowspan=2 style="text-align:right" , 56
, rowspan=2 style="text-align:right" , 91
, rowspan=2, 146.93495(22)#
, rowspan=2, 0.893(1) s
, β
− (99.94%)
,
147La
, rowspan=2, (3/2+)
, rowspan=2,
, rowspan=2,
, -
, β
−, n (.06%)
,
146La
, -
, rowspan=2,
148Ba
, rowspan=2 style="text-align:right" , 56
, rowspan=2 style="text-align:right" , 92
, rowspan=2, 147.93772(9)
, rowspan=2, 0.612(17) s
, β
− (99.6%)
,
148La
, rowspan=2, 0+
, rowspan=2,
, rowspan=2,
, -
, β
−, n (.4%)
,
147La
, -
, rowspan=2,
149Ba
, rowspan=2 style="text-align:right" , 56
, rowspan=2 style="text-align:right" , 93
, rowspan=2, 148.94258(21)#
, rowspan=2, 344(7) ms
, β
− (99.57%)
,
149La
, rowspan=2, 3/2−#
, rowspan=2,
, rowspan=2,
, -
, β
−, n (.43%)
,
148La
, -
, rowspan=2,
150Ba
, rowspan=2 style="text-align:right" , 56
, rowspan=2 style="text-align:right" , 94
, rowspan=2, 149.94568(43)#
, rowspan=2, 300 ms
, β
−
,
150La
, rowspan=2, 0+
, rowspan=2,
, rowspan=2,
, -
, β
−, n (rare)
,
149La
, -
,
151Ba
, style="text-align:right" , 56
, style="text-align:right" , 95
, 150.95081(43)#
, 200# ms
300 ns, β
−
,
151La
, 3/2−#
,
,
, -
,
152Ba
, style="text-align:right" , 56
, style="text-align:right" , 96
, 151.95427(54)#
, 100# ms
, β
−
,
152La
, 0+
,
,
, -
,
153Ba
, style="text-align:right" , 56
, style="text-align:right" , 97
, 152.95961(86)#
, 80# ms
, β
−
,
153La
, 5/2−#
,
,
See also
References
* Isotope masses from:
**
* Isotopic compositions and standard atomic masses from:
**
**
* Half-life, spin, and isomer data selected from the following sources.
**
**
**
* Half-life of
130Ba from:
**
**
{{Authority control
Barium
Barium